|| common in complete genomics
|| 2-3 fold higher risk of impulsive/aggressive behaviour when drunk
|| Increased risk for impulsive/aggressive behaviour when drunk
rs79874540, known in the literature primarily as Q20* or Q20X, represents an uncommon variant in the HTR2B gene on chromosome 2 found almost exclusively in those of Finnish origin.
A 2010 paper concluded that the rs79874540(T) variant, carried by 2.2% of the population in Finland, was associated with somewhat (2 - 3 fold?) increased risk for impulsive and/or aggressive behaviour, especially when under the influence of alcohol. The number of men studied was not particularly high.[PMID 21179162]
A 2015 follow-up study using a personality questionnaire by the same researchers of 14 heterozygous HTR2B Q20* carriers and 156 healthy controls lacking HTR2B Q20* reinforced the "aggressive when drunk" association for the Q20* allele carriers, but also noted that the Q20* carriers were neither alcoholics per se (as measured by average alcohol consumption) nor diagnosed as alcoholics, even if they had a tendency to lose behavioral control while under the influence of alcohol.[PMID 26575222]
In 2016, other Finnish researchers observed that at least for Finnish males having an antisocial personality disorder, Q20* carriers who also had low or normal testosterone levels were at lower risk for obesity than non-carriers.[PMID 27420381]